In a process of forming a semiconductor integrated circuit (IC), it is necessary to perform a cleaning process to clean various components of the semiconductor integrated circuit. A dry cleaning process, for example, a physical bombardment process, is generally used. The physical bombardment process utilities a number of free argon ions (Ar+) generated by argon (Ar) to remove oxides formed on surfaces of the components of the semiconductor integrated circuit. However, currently, the components of the semiconductor integrated circuit become smaller and smaller. For example, when a through hole formed in a component has a small size, a byproduct formed in the physical bombardment process will be deposited in the through hole. Thus, the size of the through hole will further be reduced. Further, if a surface of a silicon layer is located at the bottom of the through hole, the physical bombardment process will cause the surface of the silicon layer to be uneven, thereby generating a leakage current problem and increasing a resistance of the corresponding component.
Therefore, what is needed is a cleaning method of a semiconductor manufacturing process to overcome the above disadvantages.